This invention relates to an automatic control for wire crimping machines and more particularly to an electronic control circuit utilizing a preprogrammed microprocessor for making a wide variety of preselected crimping connections on magnet wire leads of an inductive device such as a dynamoelectric machine.
In the manufacture of dynamoelectric machines, for example, motors, the exitation windings or coils are usually made of magnet wire, i.e. copper or aluminum wire covered with a suitable layer of insulation. It has now become accepted practice to utilize semi-automatic equipment to make inexpensive crimped connections when interconnecting leads or taps from the coils of the motor with one or more other wires. However, it is also known that it is important, particularly for more demanding applications such as hermetic motors, to maintain highly precise control over the crimping operation so that the crimped connections will retain suitable conductivity characteristics over a long period of time.
Experience has shown that for the making of reliable crimped connections it is important to control the final height of the crimped connection as a function of the cross-sectional area or size of the conductors within the crimped connector. Information concerning optimum crimped connector height for given connector size is readily available from crimp connector suppliers. Thus, it has previously been found to be desirable to provide apparatus for varying the final crimped connector height and, if necessary, for feeding a "stuffer wire" to a crimping station in the crimp machine for insertion into the crimp clip just prior to performing the crimp operation. The purpose of the stuffer wire, a small piece of excess wire, is to assure that the space within the crimped connector of a given height is completely filled with conductive material so as to maintain a proper conductive relationship.
An example of one known form of mechanism for varying or quickly setting the final crimped connector height is disclosed in U.S. Pat. No. 4,051,594 issued Oct. 4, 1977 and assigned to the assignee of the present application. In this approach, a pneumatically operated lever arm and toggle linkage arrangement is provided wherein a generally L-shaped lever arm is supported at one end by a rotatable horizontal shaft, the vertical positioning of the shaft, and correspondingly the "at rest" or starting position of the crimper mechanism, is adjustable by rotation of an eccentric cam which is integrally formed on the shaft and bears against a stationary surface. The other end of the lever arm is connected to a pneumatic ram. A vertically movable crimper device is attached via a toggle link to the central portion of the lever arm by means of a pivot pin. In operation, the pneumatic ram is activated and the crimper device is lowered vertically into the operative crimp position to the exact height desired which is determined by the rotational setting of the eccentric cam. The desired rotational setting of the cam is predetermined during the equipment set-up procedure to achieve the proper crimp height with the particular crimp tooling being employed at the crimp station. In the embodiment disclosed in the aforementioned patent, the eccentric cam can be adusted to either of two different crimp height settings in the course of a complete crimping cycle. As the term is used in this specification, a complete cycle may include one or more individual crimping operations hereinafter referred to as crimp steps. Selection of the desired setting is accomplished by means of a pneumatically operated rack and pinion mechanism with adjustment of the settings being made possible by means of an adjustable stop nut arrangement on the pneumatic cylinder. However, such adjustments are normally possible only during the equipment set-up procedure, are time-consuming, and are subject to reliance on the set-up specialist for accurate setting.
It is, therefore, desirable that means be provided for establishing and automatically implementing a variety of crimp height settings to be available during one or more crimp steps of a complete crimp cycle.
It is a further object of the invention to provide control apparatus which permits convenient, reliable and rapid changing of the crimp height setting selections by the equipment operator without the necessity for relying on a mechanical set-up specialist to make the change.
As previously mentioned, it is sometimes necessary to insert an auxiliary wire piece or "stuffer wire" into the crimp connector before the actual crimp is made in order to provide a proper electrical interconnection for a given size of crimp connector. The machine of the aforementioned patent does include an automatic stuffer wire insert mechanism, however, there is no automatic means to determine the existence of an improper stuffer wire insert operation, it being left up to the operator to determine, by visual inspection, the existence of a problem and the need, therefore, to repair the connection.
Consequently, it is a further object of the present invention to provide automatic control apparatus which is responsive to an improper stuffer wire operation during the course of the stuffer operation so as to provide a readout indicative thereof automatically to the operator and to additionally provide manually actuable steps for correcting the problem.
During the course of a crimping cycle, the equipment operator may wish to interrupt automatic operation of the equipment, for example, to select a crimp step out of sequence, or to incrementally advance through discrete increments of a crimp step so as to identify and correct an improper crimp step function. There are, of course, other possible reasons for desiring to interrupt automatic sequencing of the crimp cycle. It is, therefore, a further object of the invention to provide apparatus for enabling such an interruption without losing track of the step in the cycle at which the interruption occurred so that the required step in the automatic cycle may be automatically reverted to at the completion of the interrupt operation.